Vehicle pre-delivery includes a phase that begins immediately after a vehicle is manufactured and ends when the vehicle is received by a customer, for example. In pre-delivery, vehicles may be driven out of the assembly plant, loaded onto transportation, and delivered to a dealer, where they may be moved between storage and sale lots repeatedly. In some cases, as many as 100 cold starts can occur prior to accumulation of significant mileage or complete vehicle warm-up.
In U.S. Pat. No. 5,142,479, for example, an approach is provided to reduce pre-delivery spark-plug fouling in a spark-ignition engine. Specifically, over-rich fuel-air mixtures used for reliable cold starting may cause an accumulation of carbon on the spark plugs when the engine is turned off before reaching normal operating temperatures. To reduce spark-plug fouling in a new vehicle subject to short engine run times, the enrichment value is reduced if the mileage is below 50 miles, if the coolant temperature is within set limits, and if the previous engine run time was shorter than a predetermined period of time.
The inventors herein have recognized inherent limitations in this approach, despite its potential value in reducing spark-plug fouling. In particular, other potentially degrading conditions in addition to spark-plug fouling may occur during pre-delivery, where reducing enrichment may have no effect, or worse, may cause other problems. For instance, post injection of fuel in direct injection engines may pose issues during pre-delivery. Post-injection may be used following a cold start to increase exhaust temperature, and while it may improve the NOX-reducing efficiency of an exhaust-aftertreatment device, it may also increase the rate of lubricant dilution by fuel due to cylinder bore wetting. Though the resulting risk of engine damage may be small during normal use of the vehicle, such risk may be magnified in series of frequent cold starts as occur before a new vehicle is received by a customer, such as during pre-delivery.
Therefore, in one approach, a method is provided to supply fuel to an engine of a vehicle; the method includes adjusting a direct injection of fuel into a cylinder of the engine based on whether the vehicle is in a pre-delivery state. In one example, the method includes reducing an amount of fuel in a post injection. In other examples, the method includes changing a timing of a post injection. In still other examples, the method includes changing an amount and/or a timing of a main injection of fuel, or suppressing a post injection.
By using a modified post injection schedule during pre-delivery, cylinder bore wetting effects may be reduced during the engine cold start. After pre-delivery, a normal post injection schedule may be used to reduce emissions during the engine cold start.
In accordance with this disclosure, pre-delivery may be identified in a variety of ways: based on a number of miles driven, a maximum vehicle speed, an engine run time, or combinations thereof, as examples. Further, a vehicle retailer may actuate a delivery-indicating signal once the vehicle has been delivered. Still other approaches may also be used.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.